Concept:Surface energy of a liquid drop depends on its surface area, since surface tension is constant for the same liquid.
Explanation:For a spherical drop, surface energy is given by
E=T×A.
Here
T is surface tension and
A=4πr2 is the surface area.
Since the liquid is the same,
T remains constant, so
E∝A.
Let the radius of one small drop be
r and the radius of the large drop be
R.
When 1000 small drops combine to form one large drop, the total volume is conserved.
So,
1000×34πr3=34πR3.
Cancelling common terms gives
1000r3=R3.
Taking the cube root, we get
R=10r.
Now, the ratio of surface energy of the large drop to that of one small drop is:
EsmallElarge=4πr24πR2=r2R2.
Substituting
R=10r, we get
r2(10r)2=100.
Thus, the required ratio is
100:1.
Answer:The ratio of surface energy of 1 large drop to 1 small drop is
100:1.
Correct option: A.